A Single-Ended 28-nm CMOS 6T SRAM Design with Read-assist Path and PDP Reduction Circuitry

摘要

A single-ended six-transistor (6T) SRAM cell composed of a five-transistor (5T) cell and a read-assist low-V-th PMOS as foot switch to prevent leakage damaging the data state is proposed in this work. Besides, a power-delay product (PDP) reduction circuitry design for nanoscale SRAMs is also proposed. The proposed PDP reduction circuitry design is composed of an adaptive voltage detection (AVD) circuit generating a boost-enable signal if the process variation is over a predefined range and a half-period word-line boosting (HWB) circuit responding to the enable signal. The proposed SRAM is implemented using TSMC 28-nm CMOS logic technology. PDP reduction is verified to be 41.73% according to the measurement results. The energy per access is 0.0206 pJ given the 800-mV power supply and 40-MHz system clock rate.